Multi-capacitor tone control - Page 6

Dislocardi · #**101** 09-20-2012, 11:34 AM

Er, how do you upload pics and sounds?

kringle77 · #**102** 09-20-2012, 07:19 PM

I was thinking that I would like to use the push/pull volume knob on my bass to have a preset low pass mode. So, I bought a few different cap values to try. I hooked up a cable to my bass. I then hooked two aligator clips up to the cable, then the ends of those aligator jumpers to another cable, into my amp. The signal was passed to the amp just fine. I then tied another jumper from the signal wire to a cap and then the secondary side of the cap to ground. This should be the same as turning a tone control all the way back, for the darkest setting possible but, I got nothing. I used a non-electrolytic 0.047 cap. Im not sure why it didn't work.

bumperbass · #**103** 09-20-2012, 08:22 PM

Should have worked. Did you amp go silent, like no buzz or cable noise at all? If so, maybe shorted cap. Try another.

kringle77 · #**104** 09-21-2012, 04:13 AM

I tried two othes with the same result. Doesn't make sense. Im pretty good with this stuff and have tried many different ways of hooking it up but, still nothing. Hmmm

tonebrulee · #**105** 09-21-2012, 06:31 AM

Quote:

Originally Posted by kringle77

I then tied another jumper from the signal wire to a cap and then the secondary side of the cap to ground.

What did you tie to as "ground" ?

kringle77 · #**106** 09-21-2012, 06:48 AM

The ring of the guitar cable.

tonebrulee · #**107** 09-21-2012, 07:31 AM

the ring on which guitar cable - the one on the amp side of the cap or the one on the guitar side of the cap? have you tried putting the cap directly in line with the signal? what do you hear then tonewise?

bumperbass · #**108** 09-21-2012, 07:39 AM

Quote:

Originally Posted by tonebrulee

the ring on which guitar cable - the one on the amp side of the cap or the one on the guitar side of the cap? have you tried putting the cap directly in line with the signal? what do you hear then tonewise?

It shouldn't matter which end it was. In series with the hot, it shouldn't change the tone much going into a high impedance input. It would act more like a coupling capacitor.

tonebrulee · #**109** 09-21-2012, 08:43 AM

Quote:

Originally Posted by bumperbass

It shouldn't matter which end it was.

Exactly, it shouldn't matter, and there also shouldn't be a problem here. But there is, so the next step is to check any assumptions.

kringle77 · #**110** 09-21-2012, 09:25 AM

I had already checked those options and got the same results. Im really at a loss here. My bass a redeemer circuit in it which is basically a buffer that is run after my pickup, into a volume knob, straight to the output jack. Maybe impedance matching is causing some issue, but it shouldn't be.

bumperbass · #**111** 09-21-2012, 10:17 AM

You're running a low impedance then. You're probably shorting the signal to ground. This method won't work for low impedance.

kringle77 · #**112** 09-21-2012, 10:27 AM

So it would probably work after the pickup, before the buffer?

tonebrulee · #**113** 09-21-2012, 12:43 PM

Quote:

Originally Posted by kringle77

So it would probably work after the pickup, before the buffer?

Right. That's how a typical passive tone control works - as low pass filter that shunts high frequencies to ground straight out of the pickup before the signal enters enters the volume pot. My setup to test different cap values was just to solder two leads at the points where the normal tone cap connections are made, run the leads under the pickguard so they hang outside the body. Add a couple of alligator clips to the leads and you're all set to pop in different caps.

kringle77 · #**114** 09-21-2012, 01:33 PM

Cool. I learned something today! I'll be trying this. The band has been playing alot of reggae type tunes and I would like to have a more rolled off tone sometimes. My bass only has a volume knob.

Dislocardi · #**115** 09-21-2012, 04:16 PM

Hi Kringle77,

You only need a volume knob and that switch. Tonebrulee knows his stuff man. I tried his idea of a 3 position on/on/on switch with .047 .022 and .0047 caps and ended up replacing the tone knob altogether and I must admit it sounds pretty sweet. I tried to post a mp3 sound sample of the setup but it wouldn't let me upload it. Probably because my bass sounds too pornographic now. I will try again sometime.

Tonebrulee I salute you
regards D

kringle77 · #**116** 09-21-2012, 04:29 PM

My volume is a push pull from when I origional thought that I wanted my buffered tone and sometimes the passive. The buffered is so much better that I did away with the passive all together. I can use that pull as my "pull low pass" control. Pretty cool and convenient!

tonebrulee · #**117** 09-22-2012, 08:00 PM

Quote:

Originally Posted by Dislocardi

I tried his idea of a 3 position on/on/on switch with .047 .022 and .0047 caps and ended up replacing the tone knob altogether and I must admit it sounds pretty sweet.

For round-wounds I liked that .022 value too in the middle, but for flats it ended up sounding too much like .047. I mostly play LaBella flats and went with .01 instead which I found gives a more even spread between .0047 and .047.

re: "replacing the tone knob altogether", that's how the Stellartone ToneStyler works - replacing the continuous pot with an array of discreet caps, but each cap is fully dialed in. What I like about the setup I worked out is that you maintain the tone pot, so for each cap you're still able to control how much of it you dial in.

Dislocardi · #**118** 09-23-2012, 05:50 AM

Yes I understand that mate, but I don't use my tone knob EVER. It's open sound for me fretted or fretless. So, the clearest tone possible with any given cap, it's just the ticket.

It is like the tonestyler idea I guess, except i didn't spend equivalent of $120 to achieve it.

Once again, thanks to your idea and at the risk of sounding too sycophantic, it's brilliant. I've already changed over 2 of the caps and it's getting closer to what I'm looking for. Just need to make slight alteration, no matter what I do the middle setting is always duller sounding than the 2 outer ones.

It's like you said it's FUN to experiment, try telling kids that MATHS is fun...

The link below is for a youtube vid for homemade stylerknob. Easy.

http://www.youtube.com/watch?v=3I62Xfhts9k

Jazz Ad · #**119** 09-28-2012, 11:52 AM

It lets you try different setups of cap+resistor so you get different low pass and resonant frequencies.THis is not my work, it is Dolganoff's from Onlybass.
He slowly improves on his concept and sells some readymade units.
Here's a link to the main thread but it's all in french.
http://forum.onlybass.com/index.php?...st-passif-diy/

Quote:

Originally Posted by Dislocardi

Hi jazz Ad,

That 12 position rotary switch you made looks pretty involved, could you post some more pics or at least something to explain it more clearly.

khutch · #**120** 10-02-2012, 09:48 AM

I was recently PM'd with a question about a schematic for what I did to my Reggie Hamilton to put in a passive tone control. I don't have a lot of time right now but a simple hand drawn schematic is attached. The Fender Reggie Hamilton Standard Jazz is an active P/J with an active/passive switch and a few other upgrades over standard MIM basses. Unlike the custom shop version of this bass the MIM lacks a passive tone control which makes the passive mode less useful. So I replaced the mid-band EQ pot with a Grayhill two deck rotary switch from Digikey. Then I wired several capacitors to one deck to give me a multi-capacitor tone control in passive mode and I wired some resistors to the other deck so that it can simulate the mid-band pot for the EQ in active mode.

The schematic to do that is fairly straightforward and for those who prefer wiring diagrams over schematics I would say in this case you can basically treat the schematic as a wiring diagram. It is simple enough to get you where you want to go. When you go to wire the switch into the bass you just connect the ground lead from all the capacitors to ground or the tone pot (if you use one) and the switch common terminal to the volume control where the cap would normally go. In many if not most cases if a tone pot is used it would go between the volume control and the tone cap and if that is what you are replacing just treat the switch as a capacitor and wire it in where the capacitor was. Either terminal can go where either cap lead was. You will note that I left one position open on the cap section of the switch to give a full tone, no load position.

In the bottom section resistors are soldered between each of the switch terminals (except the common) and the result is that this section of the switch acts just like a pot except that it selects a handful of discrete values instead of an infinite number of values as a true pot would. The common terminal acts like the wiper terminal on a pot and the two end terminals act like the end terminals on a pot. You can treat the pot portion of the switch in just as you would any other pot. In my case I connected the midband EQ wires from the preamp to the switch. I show a linear taper on the values by using the same resistor value between each pair of terminals but by picking the resistors appropriately you can set up any kind of a taper that you want. Likewise I show a total pot resistance of 100k but with the right resistors this can be anything you want as well.

The switch I used is a single shaft switch so that both decks are in the same position. When I shift from passive to active I may have to adjust the tone/mid switch to get the right setting for that mode but I am willing to live with that. There are some dual/concentric switches available that would allow the two settings to be independent. These switches are harder to find in stock and could easily be twice as expensive but there are some out there if you prefer. Using a dual concentric switch would allow more flexibility in using the switch. For example you could connect the cap section to the pot section and use one shaft to set the cap value and the other shaft to act as your tone pot on a passive bass.

The schematic shows only 6 positions whereas the switch I used has up to 12. If you have more or less than 6 positions you just use more or less capacitors and resistors. If you use an even number of terminals then your pot section has no middle setting (like you might want to set an EQ to the flat position) unless you short the two middle terminals together rather than putting a resistor between them and this then gives you two middle positions on the switch. The switch I used has little pins that you can use to "program" the number of allowed positions and since I thought 11 positions was plenty of cap choices and I wanted a flat position on the EQ I set up my switch to use only 11 of the 12 available positions.

Hope this helps,

Ken